1. Field of the Invention
The present invention relates to a liquid discharge apparatus such as an ink jet recording apparatus and a discharge recovery method therefor.
2. Related Background Art
For the recording apparatus such as a printer, a copying apparatus or a facsimile, and the recording apparatus (printing apparatus) used as the output device for the composite electronic equipment such as a computer or a word processor and for the work stations, there is popularly adopted the liquid discharge apparatus such as an ink jet recording apparatus for executing recording by discharging ink toward a recording medium such as paper, cloth, plastic sheet or OHP sheet. There are also various requirements for the material of such recording medium. There have recently been developments to meet such requirements, and the liquid discharge apparatus is not being used not only for ordinary recording paper (including thin paper and coated paper) or thin plastic plate (such as OHP sheet) but also for cloth, leather, non-woven cloth or even metal.
The aforementioned liquid discharge apparatus (for example ink jet recording apparatus) provides various advantages such as a low noise level, a low running cost, easy compactization of the apparatus and ease of color recording, and is therefore widely employed in the printer, copying apparatus, facsimile etc. On the front face of a liquid discharge head (ink jet recording head) of the liquid discharge apparatus, there is formed a discharge port (usually in plural units), of which size is generally about several tens of microns but is recently becoming smaller with the progress in image quality. A liquid droplet is discharged from the discharge port based on a discharge signal processed in the apparatus according to liquid discharge information (recording data) supplied from a host equipment, thereby forming an image (including a character or a symbol) on the recording medium.
In the aforementioned ink jet recording apparatus executing a recording operation by discharging ink from recording means onto the recording medium, since the recording is executed by discharging ink from a minute discharge port, there may result clogging in the discharge port to lead to defective discharge (including lack of discharge) thereby deteriorating the quality of the recorded image. As a countermeasure for such phenomenon, there is being employed a recovery unit for maintaining and recovering the ink discharge ability of the recording means. The currently employed recovery unit is for example provided with a capping mechanism for capping the discharge port of the recording head, suction means connected to the capping mechanism in the capped state and generating a negative pressure therein by the function of a pump to discharging viscosified ink or bubbles from the discharge port thereby refreshing the ink in the discharge port and maintaining and recovering the ink discharge ability, and wiping means for wiping off ink etc. deposited on the discharge port face of the recording means to achieve cleaning thereof.
In the aforementioned wiping means, in order to maintain the performance of the ink jet head constituting the liquid discharge means to be mounted on the ink jet recording apparatus constituting the liquid discharge apparatus, there is widely employed technology of cleaning the discharge port face, including the discharge port, with a wiper after a predetermined pause of the liquid discharge means following the liquid discharge of a predetermined amount therefrom or after a suction operation for eliminating the bubble or dust in the liquid discharge means. In such technology, there is proposed a method of discharging liquid (ink) from the discharge port when the wiper blade passes the discharge port in order to increasing the cleaning ability of the wiper (such liquid discharge being hereinafter called preliminary discharge).
For example the Japanese Patent Application Laid-open No. 59-45161 discloses a technology, in case of wiping the discharge port face including plural discharge ports in a direction of array of the discharge ports, of forming a discharge port not used in the image formation (recording of character etc.) at the upstream side of the wiping direction, and executing the wiping operation while discharging ink from such discharge port or executing the wiping operation while discharging ink not only from such discharge port but also from the discharge ports involved in the image formation. Also the Japanese Patent Application Laid-open No. 7-148934 discloses a technology of wetting the wiper by discharging ink thereto and eliminating the smear with thus wetted blade. Also the Japanese Patent Application Laid-open No. 11-342620 discloses a technology, in case of wiping the discharge port face including plural discharge ports in a direction perpendicular to the direction of array of the discharge ports, of improving the smear eliminating ability by utilizing ink discharge in parallel.
However, in case of executing the wiping operation in the direction of array of the discharge ports, it is found that the method of wiping after wetting the wiper in advance or the method of forming a discharge port not used for image formation at the upstream side of the wiping direction and executing the wiping direction while discharging ink from such discharge port may not be sufficient for eliminating the tough smear on the discharge port face. It is therefore conceivable to execute the wiping operation while discharging liquid (ink) from all the discharge ports, but such method requires a large amount of preliminary discharge even outside the contact area of the wiper blade with the discharge port face, thereby leading to drawbacks of smearing the main body of the liquid discharge apparatus (printing apparatus etc.) and unnecessarily large consumption of ink.
In consideration of the foregoing, the object of the present invention is to provide a liquid discharge apparatus capable of sufficiently cleaning the discharge port face while minimizing the consumption of liquid, and a discharge recovery method for such apparatus. The present invention is to control the position of the discharge port executing liquid discharge and the discharging condition thereof according to the position of the wiper in the course of the wiping operation, thereby optimizing the position and condition of liquid discharge according to the purpose of wiping.
The liquid discharge apparatus of the present invention comprises energy generating elements for generating energy to be utilized for liquid discharge, a wiper for wiping in succession plural discharge ports which discharge liquid utilizing the energy generated by the energy generating element, and control means for starting liquid discharge in succession, among the aforementioned plural discharge ports, from a discharge port immediately prior to being wiped by the wiper and a discharge port in the vicinity of the aforementioned immediately prior discharge port at the downstream side in the wiping direction of the wiper. Such liquid discharge apparatus of the present invention controls the position of the discharge port executing the liquid discharge and the discharge condition thereof according to the position of the wiper in the course of wiping operation to optimize the position and condition of the liquid discharge according to the purpose of the wiping, thereby sufficiently cleaning the discharge port face while minimizing the liquid consumption.
Also the discharge recovery method of the present invention for the liquid discharge apparatus comprises a wiping step of wiping, with a wiper, in succession plural discharge ports which discharge liquid utilizing the energy generated by energy generating elements which generate energy to be utilized for liquid discharge, and a discharge step of starting liquid discharge in succession, among the aforementioned plural discharge ports, from a discharge port immediately prior to being wiped by the wiper and a discharge port in the vicinity of the aforementioned immediately prior discharge port at the downstream side in the wiping direction of the wiper. Such discharge recovery method of the present invention for the liquid discharge apparatus controls the position of the discharge port executing the liquid discharge and the discharge condition thereof according to the position of the wiper in the course of wiping operation to optimize the position and condition of the liquid discharge according to the purpose of the wiping, thereby sufficiently cleaning the discharge port face while minimizing the liquid consumption.